The present invention relates to a novel steering system for a boat, and more particularly to a steering system for remotely controlling a rudder means through a push-pull control cable by means of a rotational operation of a steering wheel provided at an operator's seat of a boat.
Hitherto, a mechanism disclosed in the U.S. Pat. No. 3,208,300, as an example, has been known as a steering system mentioned above. As shown in FIG. 7, the conventional steering mechanism has a pinion 52 fixed to a steering shaft 51, a rack 53 being meshed with the pinion 52, an inner cable 54 of a push-pull control cable having an end portion connected with the rack 53, a rack cartridge 55 containing and guiding slidably the rack 53, and the like. Thereby, a rotational operation of a steering wheel is changed into a sliding linear motion of the inner cable 54, and a rudder means is operated.
In such a kind of steering system, since the inner cable 54 acts in the pushing direction, it is necessary to guide the inner cable 54 extending from an outer casing 57 in order to protect the inner cable 54 from buckling during the whole reciprocating stroke of the inner cable 54. Therefore, in the conventional steering system shown in FIG. 7, a rod 58 which is longer than the reciprocating stroke is connected to the end of the inner cable 54. Further, a guide pipe 59 is provided in the rack cartridge 55 or a rack casing in order to guide the inner cable 54 which comes out of the outer casing 57. That is to say, many members, e.g. the rod 58, the guide pipe 59, and the like, are employed in the conventional steering system. Further, there is a disadvantage that the construction is very complex and frictional resistance is high, since the rod 58, the guide pipe 59, the rack 53 and the rack cartridge 55 are telescopically inserted within each other. Also, the conventional system has another disadvantage that the width of the system is very wide, since a member 60 for fixing the outer casing 57 of the control cable is fastened to one end of the rack cartridge 55. Therefore, a wide space is required in the conventional system. Also, when the push-pull control cable is arranged in a narrow space of a boat, the sliding frictional resistance in the control cable becomes large, since a radius of curvature of a curved portion of the push-pull control cable becomes small.